What the site does
Publishes free calculators for load, airflow, pipe sizing, drainage, water heating, power, voltage drop, wire sizing, and related field checks.
About BuildCalcTools
Practical calculators for HVAC, plumbing, and electrical planning
BuildCalcTools helps contractors, technicians, estimators, project leads, and homeowners run quick planning calculations with visible assumptions and clear limitations.
Who it is for
People who need fast planning numbers, scenario checks, and plain-language explanations before final design or purchasing decisions.
Why it exists
To make trade calculations easier to access while keeping formulas, assumptions, mistakes, and professional limits visible.
How calculators are designed
- Inputs and outputs are named in trade-friendly language.
- Calculator pages explain the formula or planning method used.
- Result panels include interpretation, caveats, or next-step checks where useful.
- Related calculators and guides help users move through a real workflow.
- Code-sensitive topics include reminders to verify locally before final decisions.
Supported trades
HVAC
BTU load, tonnage, airflow, ductwork, hydronic flow, and efficiency calculations.
Plumbing
Pipe sizing, fixture flow, drainage, pressure drop, water heating, pump, sewer, and volume calculations.
Electrical
Watts, amps, volts, Ohm's Law, breaker sizing, wire sizing, voltage drop, energy cost, and conduit fill.
Limits and responsibility
BuildCalcTools provides planning estimates and educational guidance. It does not provide permit-ready engineering documents, replace adopted local code, or override manufacturer instructions.
Final values should be verified against site conditions, product data, jurisdictional requirements, and licensed professional judgment where required.
Corrections and feedback
If you notice a calculator error, unclear instruction, outdated reference, or broken page, please tell us. Include the calculator URL and the inputs that produced the issue.